Audio signal mixing and audio signal processing functionality is typically included in various types of audio mixing units, audio conferencing and video conferencing systems. Audio signal mixing can involve receiving a plurality of audio signals over an audio input from a microphone, for instance mixing two or more of these audio signals together and then routing the mixed audio signal(s) to one or more audio outputs, such as a loud speaker or a recording channel. Typically, audio signal mixing units include some functionality to program input signal gain levels and may also include programmable signal delay. But typically such signal mixing units do not include any complex signal processing functionality such as acoustic echo cancellation for instance. Both audio signal mixing and signal processing functionality is typically included in audio and video conferencing systems in order to mix two or more audio input signals, process them in some way (echo cancellation for instance) and send them to one or more particular audio outputs.
Commercially available audio mixing units are limited to mixing a finite number of audio signals. The audio signal mixing is usually limited by the scale/capability of the switching matrix associated with the unit. Depending upon the switching arrangement, typically eight or more audio inputs can be can be mixed and routed to eight or more audio outputs. In order to implement audio mixing systems that are capable of mixing large numbers of audio input signals, it is common practice to link individual audio signal mixing units together so that they can be controlled to mix a large number of audio inputs. A disadvantage in linking two or more audio signal mixers together is that the process of setting up the signal mixing assignments can become burdensome and error prone. In most cases, it is necessary when setting up the audio signal mix to keep track of input signals on a unit-by-unit basis as opposed to assigning the signals on a global basis. In other words, when setting up signal mixes in such a multi-unit arrangement it is necessary to specify which audio input signal on a particular unit is to be mixed with a particular audio signal either on the same unit or on another unit. Assigning mixes to input signals in such a non-global manner can be tedious at best and at worse is prone to assignment errors.
Units are commercially available that integrate audio signal mixing and signal processing systems so as to be suitable for use for audio and video conferencing applications. As with discrete signal mixing and signal processing units, integrated mixing and processing units are limited as to input signal mixing and processing capability. It therefore may be desirable to link individual, integrated audio conferencing units together to form a larger audio conferencing system. Graphical user interfaces are available that facilitate the assignment of signal mixes and signal processing in such large conferencing systems, but the signal mix assignment and the assignment of signal processing methods, as mentioned earlier, are manual in nature and operate using a block diagram or fixed signal path assignment process. An example graphical user interface is described in commonly owned patent application Ser. No. 10/644,670, the entire contents of which are incorporated herein by reference. For example, such GUIs typically necessitate keeping track of input signals on a unit-by-unit basis, as described above, rather than assigning the signals on a global basis.
The user interfaces employed to control such large, multi-unit audio conferencing systems operate to facilitate the assignment of actual, physical channel mixes between audio input signals associated with a single unit or associated with several separate, linked units. These user interfaces do not provide any facility for abstracting the actual, physical audio input signals over the entire conferencing system that will allow a user to easily assign or reassign mixes to the audio signals or to easily assign particular signal processing methods to different signals or groups of signals across the entire multi-unit system.